21481963 has 2 divisors, whose sum is σ = 21481964. Its totient is φ = 21481962.

The previous prime is 21481949. The next prime is 21482029. The reversal of 21481963 is 36918412.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21481963 is a prime.

It is a super-2 number, since 2×21481963² = 922949468666738, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21481063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10740981 + 10740982.

It is an arithmetic number, because the mean of its divisors is an integer number (10740982).

Almost surely, 2^21481963 is an apocalyptic number.

21481963 is a deficient number, since it is larger than the sum of its proper divisors (1).

21481963 is an equidigital number, since it uses as much as digits as its factorization.

21481963 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 34.

The square root of 21481963 is about 4634.8638599208. The cubic root of 21481963 is about 277.9871075573.

The spelling of 21481963 in words is "twenty-one million, four hundred eighty-one thousand, nine hundred sixty-three".